This invention relates to fluid operated stock feed apparatus for intermittently advancing strip stock along a feed path and particularly to improvements in fluid operated stock feed apparatus of the type disclosed in the applicant's prior U.S. Pat. No. 3,038,645. The stock feed apparatus disclosed in that patent in general included a stationary body, a f-uid operated stock holding clamp mounted on the body, a feed head mounted for reciprocation relative to the body and having a fluid operated stock feed clamp mounted thereon, and a fluid operated feed piston slidably mounted in a feed cylinder bore in the stationary body for extending and retracting the feed head relative to the stock holding clamp. A main control valve was mounted on the body for controlling application of fluid pressure to the fluid operated stock holding clamp and stock feed clamp, and an auxiliary valve was mounted in a stepped valve bore in the body and operated by fluid pressure from the main control valve to control the application of fluid pressure to the feed piston to extend and retract the feed head in timed relation with the operation of the stock holding and stock feed clamps.
While the prior stock feed apparatus operated satisfactorily, it was somewhat expensive to machine and assemble. It was necessary to machine a feed cylinder bore and a separate stepped valve bore in the body, and to machine numerous holes or passages in the body to interconnect the main valve and the auxiliary valve and the fluid operated stock feed and holding clamps and the fluid operated feed piston and some of these passages were at angles that were not orthogonal to the axis of the feed cylinder. The feed piston was slidably mounted directly in the feed cylinder bore and it was accordingly necessary to machine the feed cylinder bore to a smooth finish.